|Publication number||US5732344 A|
|Application number||US 08/519,521|
|Publication date||Mar 24, 1998|
|Filing date||Aug 25, 1995|
|Priority date||Aug 26, 1994|
|Also published as||DE4430314A1, DE4430314C2, EP0698964A1, EP0698964B1|
|Publication number||08519521, 519521, US 5732344 A, US 5732344A, US-A-5732344, US5732344 A, US5732344A|
|Inventors||Heinz Rinderle, Hans Sapotta|
|Original Assignee||Temic Telefunken Microelectronic Gmbh|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Referenced by (8), Classifications (11), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Mixers are frequently used in circuit design, especially in order to change the frequency of an input signal to another frequency range. One main application of this is in radio engineering where an intermediate frequency (as required in superheterodyne receiver stages, for example) is generated from the HF input signal. HF mixers are designed either as additive mixing stages, in which the input signal is fed together with an oscillator signal (LO signal) to an existing non-linear characteristic and numerous mixer products are generated on account of the non-linearity, or as multiplicative mixing stages, in which real signal multiplication is performed by means of a combined circuit made up of amplifier transistors and switching transistors. Although only very few undesired mixer products are created in multiplicative mixers, they are technically very elaborate and therefore expensive to make, so that additive mixing stages are commonly used in many frequency ranges.
As a rule, additive mixing stages are made of a bipolar transistor as mixing transistor, operated as an emitter grounded circuit or as a base grounded circuit. The LO signal can be fed either to the emitter or to the base; in the latter case, less oscillator power is needed (a high oscillator power involves more current and greater technical complexity). The mixing transistor controlled by the LO signal is either active or blocked and since the load resistance is constant, this results in amplification of the LO signal at the collector. Disadvantageous is that:
the noise of the additive mixing stage is greater and at the same time the large signal behavior is worse than is the case of an amplifier stage, so that additive mixing stages display only a low dynamic response and thus represent the weakest link in a signal transmission chain;
in a broad-band decoupling of the output signal from the mixer, disturbance signals are generated on account of the numerous undesired mixing products and harmonics;
the LO signal is transmitted to the input of the mixer; in the case of RF receivers, for example, this can result in the LO signal being radiated as disturbance signal through the antenna.
The object of the invention is to provide a HF mixer or mixing stage with advantageous features. This object generally is achieved according to the invention by a HF mixing stage for changing the frequency of an alternating voltage input signal (ES) injected at a circuit input (IN) to an output signal (AS) supplied at a circuit output (OUT), with an input signal source (ESQ) for generating the alternating voltage input signal (ES), and a local oscillator (LO) for producing a heterodyne signal (US); and wherein: the mixing stage has two transistors (T1, T2) complementary to one another and connected as base grounded circuits or gate grounded circuits respectively; both transistors (T1, T2) are connected in parallel for the alternating voltage input signal (ES); and, the two transistors (T1, T2) are connected to the local oscillator (LO) such that they are driven equidirectionally by the heterodyne signal (US) so as to cause the two transistors (T1, T2) to change to either the blocked and the conductive state simultaneously. Advantageous further developments of the invention are described.
The HF mixer presented here is designed as an additive push-pull mixing stage and has two complementary transistors operated in base grounded circuit or gate grounded circuit respectively; the transistors are arranged in such a way that in the signal branch the transistor of one polarity is connected in parallel to the transistor of the other polarity, each relating to the alternating voltage input signals. If the direct current through both transistors is identical (this can be accomplished most easily by a direct-current type of series circuit), the intermodulation products of the two transistors compensate each other. The HF mixer presented here combines several advantages:
by the compensation of the intermodulation products, a considerable increase in linearity and thus dynamic response of the mixing stage can be achieved;
since the LO current supplied from one of the two transistors at the collector or drain electrode is drawn off again, no LO components, or only very much weakened ones, appear at the collectors or drains; the LO components are therefore suppressed at the output of the mixing stage;
since the oscillator signal at the bases and gates of the transistors connected in parallel is supplied in push-pull mode, it is suppressed at the input to the mixing stage so that radiation of the LO signal (through the antenna, for example) is reduced.
To drive the complementary transistors, the LO signal must be fed to their control electrode with a phase shift of 180° . This can be accomplished either by using balancing transformers or by using electronic means.
The HF mixer for the case of bipolar transistors will be described on the basis of the drawings designated as FIGS. 1 to 4. FIGS. 1 and 2 show embodiment examples in which the emitters of the two transistors operated in base grounded circuit are connected together. FIGS. 3 and 4 show embodiment examples in which the collectors of the two transistors operated in base circuit are connected together.
In the circuit examples of FIGS. 1 and 2, the emitters of the two bipolar transistors T1 and T2 are connected together at a junction K1.
Coupling the input signal:
In accordance with FIG. 1, the alternating voltage input signal ES supplied from the input signal source ESQ is injected capacitively through the capacitor C1 at the circuit input IN to the emitters of the two transistors T1 and T2 connected together at the junction K1. In accordance with FIG. 2, the alternating voltage input signal ES supplied from the input signal source ESQ is injected inductively through the transformer U1 at the circuit input IN to the emitters of the two transistors T1 and T2 connected together at the junction K1 ; one terminal of the secondary winding of the transformer U1 joined to the circuit input IN is connected to the reference potential through capacitor C5.
The bases of the two transistors T1 and T2 are connected via frequency-dependent impedances Z1 and Z2 to the local oscillator LO that supplies the heterodyne signal US and the direct voltage source DCQ that supplies the direct voltage signal DCS. The impedances Z1 and Z2 are selected so as to be low-ohmic for the desired mixer product (for instance f1 -f2, where f1 is the frequency of the input signal ES and f2 the frequency of the heterodyne signal US). Consequently, the difference frequency signals produced at the emitters of the transistors T1 and T2 are converted without loss and with little noise to output signal AS. The direct voltage signal DCS from the direct voltage source DCQ is selected so as to allow the two transistors T1 and T2 to switch through once in the course of one period of the heterodyne signal US of the local oscillator LO.
In accordance with FIG. 1, the output signal AS at circuit output OUT is picked off at the summing point K2 from the collectors of the two transistors T1 and T2 that are connected together via capacitor C4. The collectors of transistor T1 and transistor T2 respectively are connected respectively through frequency-dependent impedances Z7 and Z8 to the positive and negative terminal of the supply direct voltage. The impedance Z7 is selected such that it is high-ohmic for the desired mixer product (for example f1 -f2) and for all other frequencies (including the frequency f=0) low-ohmic, resulting in selective amplification of the desired output signal AS (frequency f1 -f2). The impedance Z8 is selected such that it is high-ohmic for the desired mixer product and low-ohmic at least for the frequency f=0. The impedances Z7 and Z8 and thus their modes of functioning are interchangeable. In accordance with FIG. 2, the output signal AS at the circuit output OUT is picked off via the trifilar transformer U2, the first winding of which is connected to the collector of transistor T1 and the positive terminal of the supply direct voltage, and the second winding to the collector of transistor T2 and the negative terminal of the supply direct voltage, and the third winding to the circuit output OUT and the negative terminal of the supply direct voltage.
The impedances Z1, Z2, Z7 and Z8 can be of the passive or electronically active type, for example in the form of resistors, capacitors, inductors or in the form of transistors, transistor circuits etc.
In the circuit examples of FIGS. 3 and 4, the collectors of the two bipolar transistors T1 and T2 are connected together at an output junction K3.
Coupling the input signal:
In accordance with FIG. 3, the input signal ES supplied from the input signal source ESQ is injected capacitively through the two capacitors C2 and C3 connected to circuit input IN and the emitters of the two transistors T1 and T2. The emitters of the transistors T1 and T2 are connected via frequency-dependent impedances Z8 and Z7 to the negative and positive terminal respectively of the supply direct voltage; the impedances Z7 and Z8 are selected such that the parallel circuit comprising Z7 and C2 with Z8 and C3 is low-ohmic for the desired mixer product and the impedances Z8 and Z7 are low-ohmic for the frequency f=0.
In accordance with FIG. 4, the input signal ES supplied from the input signal source ESQ is injected inductively through the transformer Tr with the three windings W1, W2 and W3 to the emitters of the two transistors T1 and T2. The first winding W1 of the transformer Tr is connected at one terminal to the positive terminal of the supply direct voltage and at the other terminal to the emitter of transistor T2, the second winding W2 of transformer Tr is connected at one terminal to the negative terminal of the supply direct voltage and at the other terminal to the emitter of transistor T1, and the third winding W3 of transformer Tr is connected at one terminal to the negative terminal of the supply direct voltage and at the other terminal to the input signal source ESQ.
The output signal AS is decoupled at the output junction K3 forming the circuit output OUT (where the two collectors of the transistors T1 and T2 are connected together) via the frequency-dependent impedance Z6. The impedance Z6 is selected such that it is high-ohmic for the desired mixer product and as low-ohmic as possible for all other frequencies and for the frequency f=0 as close to infinity as possible; this results in the desired output signal AS (mixer product) being amplified selectively.
The bases of the two transistors T1 and T2 are connected through the frequency-dependent impedances Z3 and Z4 to the direct voltage sources DCQ1 and DCQ2 that supply the direct voltage signals DCS1 and DCS2 and through the frequency-dependent impedance Z5 to the local oscillator LO that supplies the heterodyne signal US. The impedances Z3 and Z4 are selected such that, for the desired mixer product, the frequency f=0 and the desired mixer frequency (for example f1 -f2) are low-ohmic and for the frequency of the heterodyne signal US high-ohmic; consequently, the heterodyne signal is not short-circuited via the direct voltage sources DCQ1 and DCQ2 respectively, and the mixer product that is produced at the emitters of transistors T1 and T2 is transferred with little noise and at no loss to the output signal AS. The impedance Z5 is selected such that it is low-ohmic for the frequency of the heterodyne signal US and very high-ohmic for the frequency f=0. The direct voltage signals DCS1 and DCS2 of the two direct voltage sources DCQ1 and DCQ2 are selected such that approximately half the supply direct voltage is applied at the collector terminal of the two transistors T1 and T2 without heterodyne signal US. The impedances Z3 to Z8 can be of the passive type (resistors, capacitors, inductors etc.) or of the electronically active type (transistors etc.).
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4032851 *||May 7, 1976||Jun 28, 1977||Rca Corporation||Complementary symmetry fet mixer circuits|
|US4080573 *||Jul 16, 1976||Mar 21, 1978||Motorola, Inc.||Balanced mixer using complementary devices|
|US4090139 *||Mar 4, 1977||May 16, 1978||Rca Corporation||Complementary symmetry FET mixer circuits|
|US4978873 *||Oct 11, 1989||Dec 18, 1990||The United States Of America As Represented By The Secretary Of The Navy||CMOS analog four-quadrant multiplier|
|US5039891 *||Dec 20, 1989||Aug 13, 1991||Hughes Aircraft Company||Planar broadband FET balun|
|US5410744 *||Feb 8, 1993||Apr 25, 1995||Temic Telefunken Microelectronic Gmbh||HF mixer stage having a common base circuit|
|US5584069 *||Jun 7, 1994||Dec 10, 1996||Temic Telefunken Microelectronic Gmbh||HF mixing stage in the form of a common-base circuit|
|DE1944081A1 *||Aug 29, 1969||Mar 11, 1971||Siemens Ag||Verstaerkender Modulator mit zwei Transistoren des einander entgegengesetzten Leitfaehigkeitstyps|
|DE2531603A1 *||Jul 15, 1975||Apr 29, 1976||Rca Corp||Verstaerker|
|DE2823789A1 *||May 31, 1978||Dec 14, 1978||Philips Nv||Modulator|
|DE4206164A1 *||Feb 28, 1992||Sep 16, 1993||Telefunken Microelectron||Hf-mischstufe in basisschaltung|
|EP0565299A1 *||Mar 31, 1993||Oct 13, 1993||Hughes Aircraft Company||Double-balanced active mixer with single-ended-to-differential voltage-current conversion circuits|
|EP0631379A1 *||Jun 3, 1994||Dec 28, 1994||TEMIC TELEFUNKEN microelectronic GmbH||HF mixer stage in common base|
|GB1574159A *||Title not available|
|GB2261130A *||Title not available|
|GB2262851A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US6072422 *||Jun 8, 1999||Jun 6, 2000||Toyota Jidosha Kabushiki Kaisha||FM-CW radar apparatus|
|US6836190 *||Feb 20, 2002||Dec 28, 2004||Murata Manufacturing Co., Ltd.||Oscillator device and electronic apparatus using the same|
|US7865157||Sep 13, 2004||Jan 4, 2011||Thomson Licensing||Controllable mixer|
|US9331738||Jan 22, 2015||May 3, 2016||Peregrine Semiconductor Corporation||Method, system, and apparatus for RF switching amplifier|
|US20030194984 *||Apr 10, 2002||Oct 16, 2003||Toncich Stanley S.||Tunable phase shifter and applications for same|
|US20050043001 *||Apr 10, 2002||Feb 24, 2005||Toncich Stanley S.||Tunable phase shifter and applications for same|
|US20070042737 *||Sep 13, 2004||Feb 22, 2007||Herbert Peusens||Controllable mixer|
|USRE38106 *||Jan 17, 2001||May 6, 2003||Lenticular Technologies||Telephone card or the like using lenticular lens material|
|U.S. Classification||455/333, 455/323, 327/356|
|International Classification||H03D7/12, H03D7/14|
|Cooperative Classification||H03D7/1491, H03D7/1425, H03D7/1433, H03D7/12|
|European Classification||H03D7/14C1, H03D7/14C|
|Sep 26, 1997||AS||Assignment|
Owner name: TEMIC TELEFUNKEN MICROELECTRONIC GMBH, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:RINDERLE, HEINZ;SAPOTTA, HANS;REEL/FRAME:008728/0594
Effective date: 19950815
|Sep 5, 2001||FPAY||Fee payment|
Year of fee payment: 4
|Oct 12, 2005||REMI||Maintenance fee reminder mailed|
|Mar 24, 2006||LAPS||Lapse for failure to pay maintenance fees|
|May 23, 2006||FP||Expired due to failure to pay maintenance fee|
Effective date: 20060324